The present invention relates to a planetary roller gear drive that converts a relative rotation between a spindle nut and a threaded spindle into a relative translational displacement between the spindle nut and threaded spindle.
From DE 8513093 U1, a planetary roller gear drive is known that is provided with a plurality of planets that are arranged distributed around the periphery and are in rolling engagement with the threaded spindle and the spindle nut, with the threaded spindle having a plurality of helical windings of at least one thread groove. These windings are wound about the spindle axis. The spindle nut is provided on its inner periphery with a nut-side profile, with the planet-side profile of the profiles in rolling engagement with the nut-side profile. The planet-side profile is formed by ring-shaped, closed grooves that are arranged perpendicular to the planet axis. The planets run on orbits that are arranged perpendicular to the spindle axis.
During the operation of such planetary roller gear drives, slippage between the threaded spindle and spindle nut can be observed if the planets circulate without sufficient axial loading. This means, for example, that for a revolution of the spindle nut, the axial advance of the threaded spindle is less than would be the case for a slip-free operation. In an extreme case, a relative rotation without axial advance can be observed.
To reduce the slippage, it is provided according to DE 8513093 U1 to divide the spindle nut into two nut parts that are arranged one behind the other in the axial direction, with an intermediate ring with a matching width being inserted between the two nut parts. The width of the intermediate ring is dimensioned so that the planets are in rolling engagement with the two nut parts and also in rolling engagement with the threaded spindle.
The width of the intermediate ring must be determined only by either calculating a width or determining the provided width with calibration rings with installed nut parts. The production of intermediate rings that are matched in width is complicated.